1. Field of the Invention
The invention relates to a blade for a turbomachine, to a shroud and to a turbomachine.
2. Discussion of Background Information
Blades of turbomachines such as gas turbines, aero engines, steam turbines and the like frequently have on their blade tips a shroud or what is referred to as an outer shroud. In the installed state of the blades, the shrouds bear against one another. By virtue of the mutual bearing, the blades are supported on the blade tip side or radially outwards with respect to an axis of rotation of the rotor, which has a vibration-damping effect. In addition, the shrouds counteract flow around the outside of the blades. In order to avoid deformations of the rather thin-walled shrouds due to high thermal and mechanical loads, these are frequently stiffened by means of a stiffening structure in the region of their surface. A fundamental increase in the thickness of the shrouds over their entire cross section can for example make it possible for disadvantageous thermal stresses to be introduced into the shrouds. An alternative measure therefore provides, for the purpose of stiffening the shrouds, to provide, on the side of the outer face or on the side of the upper face, a stiffening structure with ribs arranged in the shape of a cross with respect to one another. A shroud stiffened in this manner is for example shown in DE 10 2009 030 566 A1, the entire disclosure of which is incorporated by reference herein. Other known outer shrouds or blades of turbo machines with outer shrouds are for example shown in WO 2013/107982 A1, JP 2005207294 A and in EP 2 402 559 A1, the entire disclosures of which are incorporated by reference herein.
It would be advantageous to have available a blade for a turbomachine whose outer shroud is capable of withstanding high loads while having reduced weight. It further would be advantageous to have available a lightweight and highly loadable shroud for such a blade and a turbomachine having an optimized rotor vibration behavior.